Effect of H2 dilution on Cat-CVD a-SiC:H films

Effect of hydrogen (H2) dilution of the Silane (SiH4), acetylene (C2H2) gas mixture during the deposition of hydrogenated amorphous silicon carbon alloy (a-SiC:H) films by Cat-CVD process shows that the H2 dilution induced additional carbon incorporation, leading to an increase of the carbon content in the films from 52% to 70% for the maximum H2 dilution employed. A slight increase in graphitic carbon in the films deposited with H2 dilution is also observed. A drastic increase in the optical band gap Eg from 2.5 eV for zero dilution to 3.5 eV is observed for a H2 dilution of 10 sccm. Raman spectra for the films deposited with increasing H2 dilution indicate structural changes in the amorphous network associated with increasing graphitic carbon.